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At the request of concerned citizens living near the former Long Branch Manufactured
Gas Plant (MGP) in Long Branch, cancerincidence was evaluated for the entire city of Long
Branch and the census tract where the facility was located. Total cancer incidence and 13
specific cancer types were evaluated in this investigation. The specific cancers types were
selected because they represent cancer groupings that may be more sensitive to the effects of
environmental exposure, though not necessarily related to the specific contaminants found at the
Long Branch MGP. The results of this Health Consultation will be considered along with an
evaluation of the exposure pathways, community health concerns, and other pertinent
information in a future public health assessment of the site.

BACKGROUND AND STATEMENT OF ISSUES

The former Long Branch MGP is located within the city of Long Branch, approximately
one-quarter mile west of the Atlantic Ocean, and consists of approximately 12 acres in a
residential/commercial section of the city. The MGP facility operated from approximately 1870
through 1960 and involved the manufacture of water gas, carbureted water gas, and oil gases.
Numerous structures, including retorts, gas holders, tar separators, storage tanks and repair shops
were present on the property to support the coal-gas processes (NUS Corp, 1990). A portion of
the former MGP property was redeveloped in the 1950's by the Long Branch Housing Authority
into an apartment complex.

Characterization of the site, including areas that are currently residential, identified
numerous chemical contaminants in the environment (ARCADIS, 2002). Evaluation of on-site
soil samples detected a variety of chemical contaminants with concentrations above the New
Jersey Department of Environmental Protection's residential soil cleanup criteria including
benzene, acenaphthylene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene,
benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, indeno(1,2,3-cd)pyrene, phenanthrene,
antimony, arsenic, cadmium, copper, lead, and zinc. Many of these contaminants are part of a
broad class of chemicals called polycyclic aromatic hydrocarbons (PAHs). Potential past and
possibly current human pathways of exposure include dermal contact with contaminated soil, inhalation of vapors emanating from the contaminated soil, and ingestion of contaminated soil.

Benzene is considered to be a human carcinogen and has been associated with the
development of a particular type of leukemia called acute myeloid leukemia (ATSDR, 1997).
Exposure to PAHs have been documented to cause tumors in laboratory animals (ATSDR,
1995). PAHs are considered a probable human carcinogen based on animal experiments
(American Cancer Society, 2003a). Epidemiologic studies show that people exposed to PAHs by
breathing or skin contact for long periods to mixtures of PAHs may also have increased risk of developing cancer, especially lung and skin cancers (ATSDR, 1995).

METHODS

Study Area and Population

The Long Branch MGP study area for the evaluation of cancer incidence consisted of the
entire population residing in the town. In addition, the census tract where the facility was located
(census tract 8056) was evaluated separately. The U.S. Census Bureau designates the boundaries
for census tracts by the size of the population rather than the area of land encompassed by the
census tract.

Cancer Case Ascertainment and Study Period

The New Jersey State Cancer Registry was used for the ascertainment of cancer cases.
The Cancer Registry is a population-based cancer incidence registry covering the entire state of
New Jersey. By law, all cases of newly diagnosed cancers are reportable to the Registry. In
addition, the Registry has reporting agreements with the states of New York, Pennsylvania,
Delaware and Florida. Information on New Jersey residents who are diagnosed in those states is
supplied to the New Jersey State Cancer Registry. The Registry has been in operation since
October 1, 1978.

The study period for this investigation was January 1, 1979, through December 31, 2000.
A "case" was defined as an individual who was diagnosed with a new primary malignant cancer
during the study period while residing in Long Branch. Registry cases identified only through
search of death records were excluded from this evaluation. Information on risk factors, such as
personal lifestyle habits, are not available from the Cancer Registry.

Data Analysis

Analyses were completed for all malignant cancer types combined and for select cancer
types for the entire city of Long Branch and, separately, for the census tract where the facility was
located. The select cancer types analyzed include: bladder, brain and central nervous system
(CNS), female breast, colorectal, esophageal, pancreas, lung and pleura, leukemia, non-Hodgkin's lymphoma, liver, bone, stomach, and kidney. These cancer types were evaluated
because they represent cancer groupings that may be more sensitive to the effects of
environmental exposures. Males and females were evaluated separately. Analyses were
conducted for all races combined, Whites, and Blacks.

Standardized incidence ratios (SIR) were used for the quantitative analysis of cancer
incidence in the study areas (Kelsey, Thompson and Evans, 1986; Breslow and Day, 1987). The
SIR is calculated by dividing the observed number of cases (from the Registry) by an expected
number for the surveyed population over the time period reviewed.

The expected number was derived by multiplying a comparison population's age-sex-specific incidence rates and the study area age-sex-specific population figures. The comparison
rates used to derive the expected number of cases were the New Jersey average annual incidence
rates for 1979 to1999. The study area age-sex-specific population was determined from the
1980, 1990, and 2000 U.S. Census data (U.S. Census Bureau, 1980, 1990, 2000). Eighteen age-specific population groups were used in the analysis.

Evaluation of the observed and expected numbers is accomplished by interpreting the
ratio of these numbers. If the observed number of cases equals the expected number of cases, the
SIR will equal one (1.0). When the SIR is less than one, we conclude that fewer cases were
observed than expected. Should the SIR be greater than one, more cases than expected were
observed.

Random fluctuations may account for some SIR deviations from 1.0. Statistical
significance of deviations from SIR equal to 1.0 was evaluated using a 95% confidence interval7
(C.I.). The 95% C.I. was used to evaluate the probability that the SIR may be greater or less than
1.0 due to chance alone, and was based on the Poisson distribution (Breslow and Day, 1987;
Checkoway, Pearce, and Crawford-Brown, 1989). If the confidence interval includes 1.0, then the estimated SIR is not considered to be statistically significantly different than 1.0.

RESULTS

Table 1 presents the Long Branch population by age, race, and sex for the years 1980,
1990, and 2000. The citywide population, all races combined, dropped slightly from 1980
(29,819) to 1990 (28,658) and then rose in 2000 (31,340). The White and Black populations
followed a similar pattern with Whites comprising from 68% to 74% of the total Long Branch
population. The proportion of males increased slightly through the time period from 46% to 49% of the total population.

Census tract (CT) 8056 is one of nine census tracts in Long Branch (based on the 1990
census tracts, see Figure 1). The population in CT 8056, all races combined, dropped slightly
throughout the study period from 2,747 in 1980 to 2,621 in 1990 and 2,298 in 2000 (Table 1).
CT 8056, one of the least populated census tracts in Long Branch, had a decreasing percentage of
the total citywide population through the study period, representing 9.2% in 1980 and falling to
7.3% in 2000. The percentage of Blacks in CT 8056 was substantially higher than the city as a
whole, varying from 55% to 66% of the census tract between 1980 and 2000. From 22% to 30%
of the citywide Black population resided in CT 8056 over the study period. The proportion of
males in CT 8056 increased slightly through the time period from 42% to 47% of the total
population.

Table 2 presents the number of malignant incident cases by race, sex, and age group for
Long Branch and CT 8056. For the town as a whole, a total of 3,261 cases were diagnosed in
city residents during the years 1979-2000. Of those cases, 309 were diagnosed in residents of CT
8056. Approximately half the cases in both the city and CT 8056 were males. The distribution
of ages at time of diagnosis was similar for the city and CT 8056.

Tables 3 through 5 present cancer incidence by cancer type for all races combined,
Whites, and Blacks. The most frequently diagnosed cancer types for both Long Branch and CT
8056 include colorectal, lung, breast, and prostate, representing between 50-56% of all incident
cancers. The frequency of these cancer types is consistent with New Jersey statewide cancer
incidence data.

The purpose of this investigation was to evaluate cancer incidence in a population living
relatively near to areas contaminated by the Long Branch MGP. For the entire city of Long
Branch, the occurrence of cancer (all sites combined) over the 22-year observation period was
not higher than expected (based on average State rates) for any race-sex group evaluated.
However, brain/CNS cancers in females citywide were statistically significantly elevated for all
races combined (SIR=1.6), Whites (SIR=1.6), and Blacks (SIR=3.2). In contrast, stomach cancer
tended to be lower than expected in most race-sex groups, and statistically significantly lower in
some of the race-sex groups. Of the 81 SIRs calculated for Long Branch, four (5%) were
statistically significantly high and four (5%) were statistically significantly low. Three SIRs
(4%) were zero due to no observed cases.

For CT 8056, the census tract in which the Long Branch MGP facility was located, all
cancers combined were statistically significantly higher in males when all races were combined
(SIR=1.3) and in Black males (SIR=1.4). In addition, lung cancer was statistically significantly
elevated in all males (SIR=1.6) while esophageal cancer was statistically significantly elevated
for all females (SIR=5.7) and Black females (SIR=4.6). Brain/CNS cancers, while not
statistically significant, were elevated for Black females (SIR=4.3). Of the 81 SIRs calculated for
CT 8056, five (6%) were statistically significantly high and none were statistically significantly
low. Nineteen SIRs (24%) were zero due to no observed cases.

Cancer is a group of more than 100 different diseases (i.e., cancer types and subtypes),
each with their own set of risk factors. The multifactorial nature of cancer etiology, where a
given disease may have more than one cause, complicates the evaluation of potential risk factors
and specific disease outcomes. Benzene and PAHs, the primary contaminants at MGP site, have
been identified as possible risk factors to exposed populations for certain cancer types, primarily
leukemia (benzene) and lung cancer (PAHs). In the current analysis, the incidence of leukemia
citywide and in CT 8056 was not statistically significantly higher than expected over the study
time period. Lung cancer incidence, however, was statistically significantly higher in White
females citywide and all males in CT 8056.

While there are multiple risk factors for lung cancer, tobacco smoking is considered the
most important risk factor, estimated to account for more than 85% of all lung cancer cases
(National Cancer Institute, 1996). Other known risk factors for lung cancer include indoor
exposure to radon and environmental tobacco smoke, occupational exposure to asbestos and
other cancer-causing agents in the workplace (including radioactive ores; chemicals such as
arsenic, vinyl chloride, nickel, chromates, coal products, mustard gas, and chloromethyl ethers;
fuels such as gasoline; and diesel exhaust), and exposure to air pollution (American Cancer
Society, 2003b).

There is very limited evidence that exposure to environmental contamination is
associated with esophageal or stomach cancer risk. Occupational exposure to
tetrachloroethylene, the solvent used in dry cleaning, may lead to greater risk of esophageal
cancer (American Cancer Society, 2003c). Dry cleaning workers have a higher rate of
esophageal cancer. Also, exposure to other chemical fumes may lead to an increased risk of
esophageal cancer. However, the most important known risk factors for esophageal cancer are
consumption of alcohol and tobacco products, which account for over 80% of the risk of
squamous cell carcinoma of the esophagus (American Cancer Society, 2003c). A number of
studies have shown an association between esophageal cancer and low socioeconomic status,
independent of smoking or drinking, which may be associated with poor nutrition.

The causes of brain/CNS cancer are largely unknown, but a variety of genetic and
environmental factors have been suggested (National Cancer Institute, 1996). The only
established environmental risk factor for brain/CNS cancer is high dose ionizing radiation
(American Cancer Society, 2003d). Certain occupations and industrial exposures have also been
implicated as possible risk factors for brain/CNS cancer including chemists, embalmers,
anatomists, precision metal workers, farmers, synthetic rubber and polyvinyl chloride
manufacture, refining of crude oil and production of petroleum based chemicals, manufacture of
pharmaceuticals, and the nuclear fuels and weapons industry (National Cancer Institute, 1996).
Additionally, while there is no conclusive evidence, exposure to electromagnetic fields has also
been suggested as a possible risk factor for brain/CNS cancer.

A limitation of cancer studies of this type is the inability to assess past exposure levels in
the population. The critical piece of information required to assure a meaningful evaluation of
these data is actual personal exposure to the contamination as well as other relevant risk factors
over time; that is, who was exposed and who was not exposed and the magnitude of the exposure
that did occur. Since personal exposure information does not exist, residential distance from the
contaminated site was used as a surrogate measure for potential past exposure. This was
accomplished by analyzing separately the population living in the census tract in which the Long
Branch MGP was located. Although distance from the site may have been the best way to
estimate past potential exposures at the time the study was designed, it is also unlikely that all of
the residents in these areas were exposed to the contamination. Additionally, the length of
residence of each case is unknown, thereby potentially adding to exposure misclassification. The
consequence of exposure misclassification would be to bias the results toward not finding an
association (i.e., no exposure-health outcome relationship).

Another interpretation problem is that cancer is a chronic disease that takes many years
after exposure to manifest as clinical disease. The information supplied by the State Cancer
Registry provides only an address at time of diagnosis for each case. No information is available
on length of time an individual may have lived at the address before diagnosis. It is possible that
some cases are new, short-term residents with little or no exposure to the site. Furthermore,
former residents who have moved out of the study area just prior to diagnosis are not available
for analysis. Population mobility cannot be accounted for in this study. The current study
assumes that in and out migration of cases will offset each other.

Additionally, when researchers independently examine statistical associations for a large
number of comparisons, it is likely that some number of statistically elevated or low SIRs will
occur by chance alone. While it is possible to statistically correct for this concern, it is
controversial whether such corrections are needed. Confidence intervals are presented without adjustment for multiple comparison.

The approach utilized for this descriptive cancer investigation was "census" based, where
the entire population of Long Branch and the State of New Jersey were reviewed in order to
calculate age, sex, and race standardized incidence rate ratios for the study area. This "census"
approach (ecologic design) is a practical surveillance or screening method for cancer incidence.
Although this approach is well suited for providing a picture of cancer incidence in the specific
localities, cause-effect relationships cannot be evaluated. Important information on potential risk
factors (such as genetics, environmental factors, parental occupation, etc.) that might explain the results, were not available for analysis using this type of study design.

CONCLUSIONS AND RECOMMENDATIONS

Overall, cancer incidence (all cancers combined) was not elevated in Long Branch.
However, brain/CNS cancer was elevated in all females citywide. Lung cancer in White females
was higher than expected while stomach cancer was generally lower than expected. In CT 8056,
the area of Long Branch which had the highest potential for exposure to benzene and PAHs from
the site, excess levels of esophageal cancer in females, lung cancer in males, and all cancers
combined in males was found. Leukemia incidence citywide and in CT 8056 was not higher than
expected. While lung cancer incidence was higher in males living in CT 8056, lung cancer
incidence was not higher than expected for females in CT 8056.

This analysis of cancer incidence in the City of Long Branch and CT 8056 provides little
evidence that the rate of cancer in the study population has been affected by the potential
exposure to MGP contamination. While no further cancer analyses appear to be warranted, the
NJDHSS and ATSDR should continue to work with community representatives to determine the
most appropriate health education and outreach strategies to inform the general population about
environmental issues in the community. Additionally, the results of this Health Consultation will
be considered along with an evaluation of the exposure pathways, community health concerns, and other pertinent information in a future public health assessment of the site.

CERTIFICATION

This Health Consultation was prepared by the New Jersey Department of Health and Senior
Services (NJDHSS) under a cooperative agreement with the Agency for Toxic Substances and
Disease Registry (ATSDR). It has been produced in accordance with approved methodology and procedures existing at the time the Health Consultation was begun.